Re: [PATCH 1/3] Fix sparse checkout not removing files from index

[Jonathan Nieder <jrnieder@gmail.com>]

Nguyễn Thái Ngọc Duy wrote:

> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>

The log message left me confused.  Let’s see if the code is easier.

> +++ b/cache.h
> @@ -179,8 +179,7 @@ struct cache_entry {
>  #define CE_UNHASHED  (0x200000)
>  #define CE_CONFLICTED (0x800000)
>  
> -/* Only remove in work directory, not index */
> -#define CE_WT_REMOVE (0x400000)
> +#define CE_WT_REMOVE (0x400000) /* remove in work directory */

Before[1], CE_REMOVE was used by read-tree et al in core to represent
something to be removed from the index file and work tree (e.g., when
switching branches).

In the new order, one uses CE_REMOVE|CE_WT_REMOVE for that, right?

> +++ b/t/t1011-read-tree-sparse-checkout.sh
> @@ -147,4 +147,11 @@ test_expect_success 'read-tree adds to worktree, dirty case' '
>  	grep -q dirty sub/added
>  '
>  
> +test_expect_success 'read-tree --reset removes outside worktree' '
> +	echo init.t > .git/info/sparse-checkout &&
> +	git checkout -f top &&
> +	git reset --hard removed &&
> +	test -z "$(git ls-files sub/added)"
> +'
> +

Using reset --hard to remove a file outside the sparse checkout.
A sane, simple test; thanks.  (Nitpick: I would have used

	>empty &&
	git ls-files sub/added >output &&
	test_cmp empty output

even though that does not produce any more helpful output in this
case.)

> +++ b/unpack-trees.c
> @@ -53,6 +53,9 @@ static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
>  
>  	clear |= CE_HASHED | CE_UNHASHED;
>  
> +	if (set & CE_REMOVE)
> +		set |= CE_WT_REMOVE;
> +

A bridge between the old and new worlds.

I would have added CE_WT_REMOVE to callers instead (they all pass
constants more or less), but I suppose this way makes the patch
shorter.

[...]
> @@ -84,7 +87,7 @@ static int check_updates(struct unpack_trees_options *o)
>  	if (o->update && o->verbose_update) {
>  		for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
>  			struct cache_entry *ce = index->cache[cnt];
> -			if (ce->ce_flags & (CE_UPDATE | CE_REMOVE | CE_WT_REMOVE))
> +			if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))

Only entries marked CE_WT_REMOVE will be touched by read-tree -u.

> @@ -104,12 +107,6 @@ static int check_updates(struct unpack_trees_options *o)
>  				unlink_entry(ce);
>  			continue;
>  		}
> -
> -		if (ce->ce_flags & CE_REMOVE) {
[...]

and the CE_WT_REMOVE case takes care of that.  Makes sense.

> @@ -799,10 +796,15 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
>  			/*
>  			 * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
>  			 * area as a result of ce_skip_worktree() shortcuts in
> -			 * verify_absent() and verify_uptodate(). Clear them.
> +			 * verify_absent() and verify_uptodate().
> +			 * Make sure they don't modify worktree.
>  			 */
> -			if (ce_skip_worktree(ce))
> -				ce->ce_flags &= ~(CE_UPDATE | CE_REMOVE);
> +			if (ce_skip_worktree(ce)) {
> +				ce->ce_flags &= ~CE_UPDATE;
> +
> +				if (ce->ce_flags & CE_REMOVE)
> +					ce->ce_flags &= ~CE_WT_REMOVE;
> +			}
>  			else
>  				empty_worktree = 0;

Ah, and at last we come to the fix. :)

This is a little tricky: the CE_WT_REMOVE case (without CE_REMOVE)
represents a narrowing of the checkout and should be preserved,
while CE_WT_REMOVE|CE_REMOVE represents a removed index entry and
should be changed to just CE_REMOVE.

But it is a clear improvement over the code from before and should
behave as advertised now.  So aside from the log message,

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

Thanks.

[1] v1.6.6.1~23^2~1 (Make on-disk index representation separate from
in-core one, 2008-01-14) and v0.99~295 (git-read-tree: remove deleted
files in the working directory, 2005-06-09).